Under 700℃ working condition, what material of bolts should the Class900 flange be equipped with? Conflicting standards
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I checked HG/T 20634. The 304 mentioned above is a low-strength material and can only be used for flanges below Class 300. The problem is that the maximum service temperature of other medium- and high-strength materials is only 525°C. This makes me depressed. So which material should I choose as a fastener?
Your description is contradictory. 304 does not have the restrictions you mentioned.
Please carefully read the sentence below the first table I sent. 304 is a low-strength material and can only be used for flanges below Class 300. My working conditions are above 700°C and the pressure is very high, so I need to choose at least a class900 flange. In this case, I can't choose according to this standard. High-strength materials can only be used in working conditions below 525°C, and 304 cannot be used on 900 flanges.
Give it a try, why did it sink? Anyone who has done research on this please reply and let me know.
There does seem to be a problem: This table says that 304 can be used below CL2500
This post was last edited by Yuyu in the Desert on 2020-7-12 11:55. I really don’t understand this. I know a lot about high temperature gaskets, you can contact me
In fact, I understand that ≤Class2500 in this table means that some of these materials can be used up to Class 2500, not all materials can be used up to Class 2500.
Please help me, I also want to know the result.
I just want to know what material you use for the valve body? The bolts can’t stand it, what should you do with your valve body? If the valve body is OK, then find a bar material that is similar or better than the valve body material and customize the non-standard bolts yourself!
The valve body is actually made of 347 stainless steel and is manufactured according to Class1500 standards. Our previous working temperature was lower, and we used 304 fasteners over 600 degrees, but there has been no problem. Now that we are going to use it under working conditions of more than 700 degrees, I wanted to check the standard to see what material is more suitable. I found that this is stipulated in the standard.